Replaces the opaque BASCULE_ATTESTATION_HASH (a SHA over a
"pcrN:val;ima:hash;" evidence string) with a real proto-canonical
SatBundle composed from the operator's identity + local platform
attestation, anchored on the L4 SessionClaim.
bascule-core::sat (NEW): pure composer module.
- build_session_claim(SessionInputs) -> SessionClaim builds the
L4 leaf from {principal, auth_method, actor_type,
identity_verified, platform_attested, software_verified,
nonce_seed}, computes posture per SAT-SPEC-0002 §7, and
populates the L1/L2/L3 binding fields with zero-padded
placeholders until upstream producers exist.
- compose_local(SessionClaim) -> ComposedSat assembles the proto
SatBundle via SatBundleBuilder. Hot path stays local per ADR D9
(zero network); QM's gRPC ComposeSat is the warm-path surface.
- 7 unit tests cover layer/actor wiring, posture math at each
evidence level, deterministic nonce, sat_hash uniqueness across
principal changes.
bascule-shell: composes the SAT in main() right before execvp
of the inner shell — that's the OSS equivalent of an "Authenticated
-> ShellActive" transition (the OSS Bascule has no russh state
machine; it's a CLI wrapper). Exports the new env var surface:
BASCULE_SAT_HASH hex of proto sat_hash (canonical)
BASCULE_SESSION_CLAIM_HASH hex of L4 leaf hash
BASCULE_SESSION_ID UUID from SessionClaim
BASCULE_POSTURE_LEVEL SAT-SPEC-0002 §7 posture
BASCULE_ATTESTATION_HASH retained as compat alias (gsh /
dashboard consumers); now points at
the proto sat_hash, not the old
evidence-string SHA.
Cross-workspace path dep: substrate-proto via
../substrate-project/substrate/crates/substrate-proto. CI mounts
~/projects as one volume so the path resolves. Switching to a git
dep is post-MVP.
Note: russh-keys pulls `home` which requires Rust 1.88; CI bumps
the docker image accordingly. No code change.
Tested:
cargo build -p bascule-core -p bascule-shell clean
cargo test -p bascule-core --lib sat 7/7
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Signed-off-by: Claude Code <claude@guildhouse.dev>
New crate: bascule-shell (471 lines, 1.8MB binary)
Login shell that detects identity + platform attestation at startup.
Wraps bash/zsh/fish — operator works normally, identity travels with them.
Identity detection (priority order):
1. Entra via WSL2 interop
2. Azure CLI
3. Kerberos TGT
4. Cached OIDC token
5. System user (fallback)
Platform attestation:
TPM 2.0 PCR values via tpm2_pcrread (PCRs 0,1,2,7,10,14)
IMA measurement log hash + count
Keylime agent state
Entra device compliance (WSL2 only)
Composite SHA-256 hash over all evidence
Shell features:
Banner with identity + attestation summary
BASCULE_* env vars injected into inner shell
--info mode for dry-run display
--json mode for machine-readable output
--exec mode for single-command execution
Configurable via ~/.config/bascule/shell.toml
Tested on Fedora with real TPM 2.0:
6 PCRs successfully read from hardware
All env vars propagated to inner shell
1.8MB binary, 0 substrate deps
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
